I've seen relatives of murdered people complain that murder jokes are still socially acceptable.

That's the subject of the first couple minutes of This American Life episode 342.

[A]t the Parents of Murdered Children Conference, they have [a presentation on] murder mystery dinners. And the way that they always do it is they say, let's just pretend that you were going to have a rape mystery dinner and you were going to show up and the rule of the game was going to be that someone's been raped, and we're all going to find the rapist. That wouldn't go over. Nobody would do it. Everybody would feel that that was deeply distasteful.

(Transcript here.)